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August 7, 2014December 23, 2015 by Ken Kremer

What’s Ahead for Rosetta – ‘Finding a Landing Strip’ on Bizarre Comet 67P/Churyumov-Gerasimenko

NAVCAM image taken by Rosetta on 5 August 2014 from a distance of about 145 km from comet 67P/Churyumov-Gerasimenko. Image has been rotated 180 degrees. Credit: ESA/Rosetta/NAVCAM

Where would you land here?
Newly released NAVCAM image taken by Rosetta on 5 August 2014 from a distance of about 145 km from comet 67P/Churyumov-Gerasimenko. Image has been rotated 180 degrees. Credit: ESA/Rosetta/NAVCAM[/caption]

Following the flawless and history making arrival of the European Space Agency’s (ESA) Rosetta spacecraft at its long sought destination of Comet 67P/Churyumov-Gerasimenko on Wednesday, Aug. 6, the goal of conducting ground breaking science at this utterly alien and bizarre icy wanderer that looks like a ‘Scientific Disneyland’ can actually begin.

Rosetta is the first spacecraft in history to rendezvous with a comet and enter orbit – after a more than 10 year chase of 6.4 billion kilometers (4 Billion miles) along a highly complex trajectory from Earth. The arrival event was broadcast live from mission control at ESA’s spacecraft operations centre (ESOC) in Darmstadt, Germany. Read my complete arrival story – here.

So what’s ahead for Rosetta? Another audacious and history making event – Landing on the comet!

A top priority task is also another highly complex task – ‘Finding a landing strip’ on the bizarre world of Comet 67P for the piggybacked Philae comet lander equipped with 10 science instruments.

“The challenge ahead is to map the surface and find a landing strip,” said Andrea Accomazzo, ESA Rosetta Spacecraft Operations Manager, at the Aug. 6 ESA webcast.

That will be no easy task based on the spectacular imagery captured by the OSIRIS high resolution science camera and the Navcam camera that has revealed an utterly wacky and incredibly differentiated world like none other we have ever visited or expected when the mission was conceived.

Magnificently detailed new navcam images were released by ESA today, Aug, 7, streaming back to Earth across some 405 million kilometers (250 million miles) of interplanetary space – see above and below.

The team will have its hand full trying to find a safe spot for touchdown.

“We now see lots of structure and details. Lots of topography is visible on the surface,” said Holger Sierks, principal investigator for Rosetta’s OSIRIS camera from the Max Planck Institute for Solar System Research in Gottingen, Germany, during the webcast.

“There is a big depression and 150 meter high cliffs, rubble piles, and also we see smooth areas and plains. It’s really fantastic”

“We see a village of house size boulders. Some about 10 meters in size and bigger and they vary in brightness. And some with sharp edges. We don’t know their composition yet,” explained Sierks.

Newly released NAVCAM image taken on 6 August 2014 from a distance of about 96 km from comet 67P/Churyumov-Gerasimenko. Credit: ESA/Rosetta/NAVCAM

The key to finding a safe landing site for Philae will be quickly conducting a global comet mapping campaign with OSIRIS, Navcam and the remaining suite of 11 science instruments to provide a detailed scientific study of the physical characteristics and chemical composition of the surface.

They also need to determine which areas are hard or soft.

Holger Sierks, OSIRIS principal investigator, discuss spectacular hi res comet images returned so far by Rosetta during the Aug. 6 ESA webcast from mission control at ESOC, Darmstadt, Germany. Credit: Roland Keller — Holger Sierks, OSIRIS principal investigator, discusses spectacular hi res comet images returned so far by Rosetta during the Aug. 6 ESA webcast from mission control at ESOC, Darmstadt, Germany. Credit: Roland Keller

“Our first clear views of the comet have given us plenty to think about,” says Matt Taylor, ESA’s Rosetta project scientist.

“Is this double-lobed structure built from two separate comets that came together in the Solar System’s history, or is it one comet that has eroded dramatically and asymmetrically over time? Rosetta, by design, is in the best place to study one of these unique objects.”

Yesterday’s (Aug. 6) critical final thruster firing placed the 1.3 Billion euro robotic emissary from Earth into a triangular shaped orbit about 100 kilometers (62 miles) above and in front of the comet’s incredibly varied surface.

Therefore the initial mapping will be conducted from the 100 km (62 mi.) standoff distance.

Since the landing is currently targeted for November 11, 2014, in barely three months time there is not a moment to waste.

“Over the next few months, in addition to characterizing the comet nucleus and setting the bar for the rest of the mission, we will begin final preparations for another space history first: landing on a comet,” says Taylor.

The team will identify up to five possible landing sites by late August and expect to choose the primary site by mid-September.

Then the team has to plan and build the programming and maneuvers for the final timeline to implement the sequence of events leading to the nailbiting landing.

With Rosetta now travelling in a series of 100 kilometer-long (62 mile-long) triangular arcs in front of the comet lasting about 3 days each, it will also be firing thrusters at each apex.

After catching up with the comet Rosetta will slightly overtake and enter orbit from the ‘front’ of the comet as both the spacecraft and 67P/CG move along their orbits around the Sun. Rosetta will carry out a complex series of manoeuvres to reduce the separation between the spacecraft and comet from around 100 km to 25-30 km. From this close orbit, detailed mapping will allow scientists to determine the landing site for the mission’s Philae lander. Immediately prior to the deployment of Philae in November, Rosetta will come to within just 2.5 km of the comet’s nucleus. This animation is not to scale; Rosetta’s solar arrays span 32 m, and the comet is approximately 4 km wide. Credit: ESA–C. Carreau

But it will also gradually edge closer over the next six weeks to about 50 km distance and then even closer to lower Rosetta’s altitude about Comet 67P until the spacecraft is captured by the comet’s gravity.

In November 2014, Rosetta will attempt another historic first when it deploys the Philae science lander from an altitude of just about 2.5 kilometers above the comet for the first ever attempt to land on a comet’s nucleus.

The three-legged lander will fire harpoons and use ice screws to anchor itself to the 4 kilometer (2.5 mile) wide comet’s surface. Philae will collect stereo and panoramic images and also drill into and sample its incredibly varied surface.

How will Philae land?

Stefan Ulamec, Philae Lander Manager from the German Aerospace Center (DLR) talked about the challenges of landing in a low gravity environment during the ESA webcast.

“The touchdown will be at a speed of just 1 m/s,” Ulamec explained. “This is like walking and bouncing against a wall.”

Details in an upcoming story!

Why study comets?

Comets are leftover remnants from the formation of the solar system. Scientists believe they delivered a vast quantity of water to Earth. They may have also seeded Earth with organic molecules.

Stay tuned here for Ken’s continuing Rosetta, Curiosity, Opportunity, Orion, SpaceX, Boeing, Orbital Sciences, commercial space, MAVEN, MOM, Mars and more Earth and Planetary science and human spaceflight news.

Ken Kremer

…….

Read my Rosetta series here:

Rosetta Arrives at ‘Scientific Disneyland’ for Ambitious Study of Comet 67P/Churyumov-Gerasimenko after 10 Year Voyage

Rosetta on Final Approach to Historic Comet Rendezvous – Watch Live Here

Rosetta Probe Swoops Closer to Comet Destination than ISS is to Earth and Reveals Exquisite Views

Rosetta Orbiter less than 500 Kilometers from Comet 67P Following Penultimate Trajectory Burn

Rosetta Closing in on Comet 67P/Churyumov-Gerasimenko after Decade Long Chase

August 6, 2014December 23, 2015 by Ken Kremer

Rosetta Arrives at ‘Scientific Disneyland’ for Ambitious Study of Comet 67P/Churyumov-Gerasimenko after 10 Year Voyage

The image of Comet 67P/Churyumov-Gerasimenko was taken by Rosetta’s OSIRIS narrow-angle camera on 3 August 2014 from a distance of 285 km. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
Story updated[/caption]

“We’re at the comet! Yes,” exclaimed Rosetta Spacecraft Operations Manager Sylvain Lodiot, confirming the spacecraft’s historic arrival at Comet 67P/Churyumov-Gerasimenko during a live webcast this morning, Aug. 6, from mission control at ESA’s spacecraft operations centre (ESOC) in Darmstadt, Germany.

The European Space Agency’s (ESA) Rosetta comet hunter successfully reached its long sought destination after a flawless orbital thruster firing at 11 AM CEST to become the first spacecraft in history to rendezvous with a comet and enter orbit aimed at an ambitious long term quest to produce ground breaking science.

“Ten years we’ve been in the car waiting to get to scientific Disneyland and we haven’t even gotten out of the car yet and look at what’s outside the window,” Mark McCaughrean, senior scientific adviser to ESA’s Science Directorate, said during today’s webcast. “It’s just astonishing.”

“The really big question is where did we and the solar system we live in come from? How did water and the complex organic molecules that build up life get to this planet? Water and life. These are the questions that motivate everybody.”

“Rosetta is indeed the ‘rosetta stone’ that will unlock this treasure chest to all comets.”

Today’s rendezvous climaxed Rosetta’s decade long and 6.4 billion kilometers (4 Billion miles) hot pursuit through interplanetary space for a cosmic kiss with Comet 67P while speeding towards the inner Solar System at nearly 55,000 kilometers per hour.

The probe is sending back spectacular up close high resolution imagery of the mysterious binary, two lobed comet, merged at a bright band at the narrow neck of the celestial wanderer that looks like a ‘rubber ducky.’

“This is the best comet nucleus ever resolved in space with the sharpest ever views of the nucleus, with 5.5.meter pixel resolution,” said Holger Sierks, principal investigator for Rosetta’s OSIRIS camera from the Max Planck Institute for Solar System Research in Gottingen, Germany, during the webcast.

Back side view of Comet 67P/Churyumov-Gerasimenko was taken by Rosetta’s OSIRIS narrow-angle camera on 3 August 2014 from a distance of 285 km. The image resolution is 5.3 metres/pixel. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

“We now see lots of structure and details. Lots of topography is visible on the surface. We see the nucleus and outgassing activity. The outbursts are seen with overexposed images. It’s really fantastic”

“There is a big depression on the head and 150 meter high cliffs, rubble piles, and also we see smooth areas and plains. The neck is about 1000 meters deep and is a cool area. There is outgassing visible from the neck.”

“We see a village of house size boulders. Some about 10 meters in size and bigger they vary in brightness. And some with sharp edges. We don’t know their composition yet.”

“We don’t understand how its created yet. That’s what we’ll find out in coming months as we get closer.”

“Rosetta has arrived and will get even closer. We’ll get ten times the resolution compared to now.”

“The comet is a story about us. It will be the key in cometary science. Where did it form? What does it tell us about the water on Earth and the early solar system and where it come from?”

Following the blastoff on 2 March 2004 tucked inside the payload fairing of an Ariane 5 G+ rocket from Europe’s spaceport in Kourou, French Guiana, Rosetta traveled on a complex trajectory.

It conducted four gravity assist speed boosting slingshot maneuvers, three at Earth and one at Mars, to gain sufficient velocity to reach the comet, Lodiot explained.

The 1.3 Billion euro robotic emissary from Earth is now orbiting about 100 kilometers (62 miles) above the comet’s surface, some 405 million kilometers (250 million mi.) from Earth, about half way between the orbits of Jupiter and Mars.

The main event today, Aug. 6, was to complete an absolutely critical thruster firing which was the last of 10 orbit correction maneuvers (OCM’s). It started precisely on time at 11:00 AM CEST/09:00 GMT/5:00 AM EST, said Lodiot. The signal was one of the cleanest of the entire mission.

The orbital insertion engine firing dubbed the Close Approach Trajectory – Insertion (CATI) burn was scheduled to last about 6 minutes 26 seconds. Confirmation of a successful burn came some 28 minutes later.

“We’re at the comet! Yes,” Lodiot excitedly announced live whereupon the crowd of team members, dignitaries and journalists at ESOC erupted in cheers.

For the next 17 months, the probe will escort comet 67P as it loops around the Sun towards perihelion in August 2015 and then continue along on the outbound voyage towards Jupiter.

ESA’s incredibly bold mission will also deploy the three-legged piggybacked Philae lander to touch down and drill into and sample its incredibly varied surface a little over three months from now.

Together, Rosetta and Philae are equipped with a suite of 21 science instruments to conduct an unprecedented investigation to characterize the 4 km wide (2.5 mi.) comet and study how the pristine frozen body composed of ice and rock is transformed by the warmth of the Sun.

Comets are believed to have delivered a vast quantity of water to Earth. They may have also seeded Earth with organic molecules.

Close-up detail of comet 67P/Churyumov-Gerasimenko. The image was taken by Rosetta’s OSIRIS narrow-angle camera and downloaded today, 6 August. The image shows the comet’s ‘head’ at the left of the frame, which is casting shadow onto the ‘neck’ and ‘body’ to the right. The image was taken from a distance of 120 km and the image resolution is 2.2 metres per pixel. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA — Close-up detail of comet 67P/Churyumov-Gerasimenko. The image was taken by Rosetta’s OSIRIS narrow-angle camera and downloaded today, 6 August. The image shows the comet’s ‘head’ at the left of the frame, which is casting shadow onto the ‘neck’ and ‘body’ to the right.
The image was taken from a distance of 120 km and the image resolution is 2.2 metres per pixel. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Rosetta and Philae will also search for organic molecules, nucleic acids and amino acids, the building blocks for life as we know it by sampling and analyzing the comets nucleus and coma cloud of gas and dust.

“The first coma sampling could happen as early as next week,” said Matt Taylor, ESA’s Rosetta project scientist on the webcast.

After thoroughly mapping the comet, the team will command Rosetta to move even lower to 50 km altitude and then even lower to 30 km and less.

The scientists and engineers will search for up to five possible landing sites for Philae to prepare for the touchdown in mid-November 2014.

“We want to characterize the nucleus so we can land in November,” said Taylor. “We will have a ringside along with the comet as it moves inwards to the sun and then further out.”

Comet 67P/Churyumov-Gerasimenko activity on 2 August 2014. The IMAGE was taken by Rosetta’s OSIRIS wide-angle camera from a distance of 550 km. The exposure time of the image was 330 seconds and the comet nucleus is saturated to bring out the detail of the comet activity. Note there is a ghost image to the right. The image resolution is 55 metres per pixel. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Studying comets will shed light on the history of water and life on Earth.

“We are going to places we have never been to before,” said Jean-Jacques Dordain, ESA’s Director General during the webcast.

“We want to get answers to questions to the origin to water and complex molecules on Earth. This opens up even more new questions than answers.”

Watch for updates.

Ken Kremer

……..

Read my Rosetta series here:

Rosetta on Final Approach to Historic Comet Rendezvous – Watch Live Here

Rosetta Probe Swoops Closer to Comet Destination than ISS is to Earth and Reveals Exquisite Views

Rosetta Orbiter less than 500 Kilometers from Comet 67P Following Penultimate Trajectory Burn

Rosetta Closing in on Comet 67P/Churyumov-Gerasimenko after Decade Long Chase

August 5, 2014December 23, 2015 by Ken Kremer

Rosetta on Final Approach to Historic Comet Rendezvous – Watch Live Here

ESA’s Rosetta spacecraft on final approach to Comet 67P/Churyumov-Gerasimenko in early August 2014. This collage of navcam imagery from Rosetta was taken on Aug. 1, 2, 3 and 4 from distances of 1026 km, 500 km, 300 km and 234 km. Not to scale. Credit: ESA/Rosetta/NAVCAM – Collage/Processing: Marco Di Lorenzo/Ken Kremer- kenkremer.com
Watch ESA’s Live Webcast here on Aug. 6 starting at 4 AM EDT/ 8 AM GMT[/caption]

After a decade long chase of 6.4 billion kilometers (4 Billion miles) through interplanetary space the European Space Agency’s (ESA) Rosetta spacecraft is now on final approach for its historic rendezvous with its target comet 67P scheduled for Wednesday morning, Aug. 6. some half a billion kilometers from the Sun. See online webcast below.

Rosetta arrives at Comet 67P/Churyumov-Gerasimenko in less than 12 hours and is currently less than 200 kilometers away.

You can watch a live streaming webcast of Rosetta’s Aug. 6 orbital arrival here, starting at 10:00 a.m. CEST/8 a.m. GMT/4 a.m. EDT/1 a.m. PDT via a transmission from ESA’s spacecraft operations centre in Darmstadt, Germany.

Rosetta is the first mission in history to rendezvous with a comet and enter orbit around it. The probe will then escort comet 67P as it loops around the Sun, as well as deploy the piggybacked Philae lander to its uneven surface.

eurospaceagency on livestream.com. Broadcast Live Free

Orbit entry takes place after the probe initiates the last of 10 orbit correction maneuvers (OCM’s) on Aug. 6 starting at 11:00 CEST/09:00 GMT.

The thruster firing, dubbed the Close Approach Trajectory – Insertion (CATI) burn, is scheduled to last about 6 minutes 26 seconds. Engineers transmitted the commands last night, Aug. 4.

CATI will place the 1.3 Billion Euro Rosetta into an initial orbit at a distance of about 100 kilometers (62 miles).

Since the one way signal time is 22 min 29 sec, it will take that long before engineers can confirm the success of the CATI thruster firing.

As engineers at ESOC mission control carefully navigate Rosetta ever closer, the probe has been capturing spectacular imagery showing rocks, gravel and tiny crater like features on its craggily surface with alternating smooth and rough terrain and deposits of water ice.

See above and below our collages (created by Marco Di Lorenzo & Ken Kremer) of navcam camera approach images of the comet’s two lobed nucleus captured over the past week and a half. Another shows an OSIRIS camera image of the expanding coma cloud of water and dust.

The up close imagery revealed that the mysterious comet looks like a ‘rubber ducky’ and is comprised of two lobes merged at a bright band at the narrow neck in between.

Rosetta’s navcam camera has been commanded to capture daily images of the comet that rotates around once every 12.4 hours.

After orbital insertion on Aug. 6, Rosetta will initially be travelling in a series of 100 kilometer-long (62 mile-long) triangular arcs in front of the comet while firing thrusters at each apex. Further engine firings will gradually lower Rosetta’s altitude about Comet 67P until the spacecraft is captured by the comet’s gravity.

Rosetta will continue in orbit at comet 67P for a 17 month long study.

In November 2014, Rosetta will attempt another historic first when it deploys the piggybacked Philae science lander from an altitude of just about 2.5 kilometers above the comet for the first ever attempt to land on a comet’s nucleus. The lander will fire harpoons to anchor itself to the 4 kilometer (2.5 mile) wide comet’s surface.

Together, Rosetta and Philae will investigate how the pristine frozen comet composed of ice and rock is transformed by the warmth of the Sun. They will also search for organic molecules, nucleic acids and amino acids, the building blocks for life as we know it.

Rosetta was launched on 2 March 2004 on an Ariane 5 G+ rocket from Europe’s spaceport in Kourou, French Guiana.

Ken Kremer

August 4, 2014December 23, 2015 by Ken Kremer

Rosetta Probe Swoops Closer to Comet Destination than ISS is to Earth and Reveals Exquisite Views

NAVCAM image taken on 3 August 2014 from a distance of about 300 km from comet 67P/Churyumov-Gerasimenko. The Sun is towards the bottom of the image in this orientation. Credits: ESA/Rosetta/NAVCAM

Europe’s Rosetta comet hunter achieved another milestone today, Aug 4, swooping in closer to its long sought destination than the International Space Station (ISS) is to Earth – and its revealing the most exquisitely sharp and detailed view yet of the never before visited icy wanderer soaring half a billion kilometers from the Sun.

The absolutely delightful photo above is the latest navcam taken of Comet 67P/Churyumov-Gerasimenko by Rosetta’s navcam camera on Aug. 3 from a distance of 300 kilometers and shows rocks, gravel and tiny crater like features on its craggily surface of smooth and rough terrain with deposits of water ice.

Rosetta will make history as Earth’s first probe ever to rendezvous with and enter orbit around a comet.

Now barely a day away from rendezvous, the European Space Agency’s (ESA) robotic Rosetta spacecraft has closed to a distance of less than 300 kilometers away from Comet 67P and the crucial orbital insertion engine firing.

By comparison, the ISS and its six person crew orbits Earth at an altitude of some 400 kilometers (about 250 miles).

And its getter even closer! – Essentially to what we would call ‘the edge of space’ on Earth; 100 kilometers or 62 miles.

Having successfully completed the penultimate orbit correction maneuver on Aug. 3, the engineering team at mission control at the European Space Operations Centre (ESOC), in Darmstadt, Germany is making final preparations for the probes crucial last orbital insertion burn set for Wednesday, Aug. 6.

The Aug. 3 thruster firing known as the Close Approach Trajectory – pre-Insertion (CATP) burn lasted some 13 minutes and 12 seconds and reduced the spacecraft speed as planned by about 3.2 m/s.

“All looks good,” says Rosetta Spacecraft Operations Manager Sylvain Lodiot, according to an ESA operations tweet.

The final thruster firing upcoming soon on Aug. 6 is known as the Close Approach Trajectory – Insertion (CATI) burn.

The CATI orbit insertion firing will slow Rosetta to essentially the same speed as comet 67P and place it in an initial orbit at a distance of about 100 kilometers (62 miles).

The CATP and CATI trajectory firings have the combined effect of slowing Rosetta’s speed by some 3.5 m/s with respect to the comet which is traveling at 55,000 kilometers per hour (kph).

After a ten year chase of 6.4 billion kilometers (4 Billion miles) through interplanetary space and slingshots past Earth and Mars, the 1.3 Billion Euro spacecraft is at last ready to arrive at Comet 67P for a mission expected to last some 17 months.

The Navcam camera has been commanded to capture daily images of the comet that rotates around once every 12.4 hours.

See below our mosaic of navcam camera approach images of the nucleus captured of the mysterious two lobed comet, merged at a bright band in between as well as an OSIRIS camera image of the expanding coma cloud of water and dust..

After orbital inertion on Aug. 6, Rosetta will initially be travelling in a series of 100 kilometer-long triangular arcs while firings thrusters at each apex. Further engine firings will gradually lower Rosetta’s altitude about Comet 67P until the spacecraft is captured by the comet’s gravity.

Here is an ESA video showing Rosetta’s movements around the comet after arrival

Video caption: ESA’s Rosetta spacecraft will reach comet 67P/Churyumov-Gerasimenko in August 2014. After catching up with the comet Rosetta will slightly overtake and enter orbit from the ‘front’ of the comet as both the spacecraft and 67P/CG move along their orbits around the Sun. Rosetta will carry out a complex series of manoeuvres to reduce the separation between the spacecraft and comet from around 100 km to 25-30 km. Credit: ESA

Rosetta was launched on 2 March 2004 on an Ariane 5 G+ rocket from Europe’s spaceport in Kourou, French Guiana.

You can watch Rosetta’s Aug. 6 orbital arrival live from 10:45-11:45 CEST via a livestream transmission from ESA’s spacecraft operations centre in Darmstadt, Germany.

Ken Kremer

August 3, 2014December 23, 2015 by Ken Kremer

Rosetta Orbiter less than 500 Kilometers from Comet 67P Following Penultimate Trajectory Burn

The Rosetta comet chaser is currently less than 500 kilometers (300 miles) from its target destination, Comet 67P/Churyumov-Gerasimenko following today’s (Aug. 3) successful completion of the spacecraft’s critically important penultimate trajectory burn, just three days before its history making arrival at the comet on Aug. 6.

The European Space Agency’s (ESA) 1.3 Billion euro Rosetta spacecraft is now under three days away from becoming Earth’s first probe ever to rendezvous with and enter orbit around a comet after a decade long hunt of 6.4 billion kilometers (4 Billion miles) through interplanetary space. The gap is narrowing with each passing second.

The last trajectory firing is set for Aug. 6. Altogether the final pair of trajectory burns will reduce the spacecrafts speed by some 3.5 meters per second (m/s) with respect to the comet which is traveling at 55,000 kilometers per hour (kph).

The probes latest Navcam camera image shot on Aug. 2, 2014 from a distance of about 500 kilometers from comet 67P/Churyumov-Gerasimenko shows exquisite detail of the rubber ducky shaped body tumbling end over end. See above.

See below our mosaic of navcam camera approach images of the nucleus captured over the past week and a half of the mysterious two lobed comet, merged at a bright band in between.

In November 2014, the Rosetta mothership will attempt another historic first when it deploys the Philae science lander from an altitude of just 1 or 2 kilometers for the first ever attempt to land on a comet’s nucleus. The lander will fire harpoons to anchor itself to the 4 kilometer wide (2.5 mile) comet’s surface.

Did life on Earth begin with the help of comet seeding? That’s a question the Rosetta science team seeks to help answer.

Today’s early morning thruster firing, officially known as the Close Approach Trajectory – pre-Insertion (CATP) burn, began as scheduled at 11:00 CEST (09:00 GMT) and was due to last for about 13 minutes and 12 seconds and bleed off some 3.2 m/s of spacecraft speed.

Although it ended a few seconds early, ESA reports that the CATP burn went well as engineers monitored the spacecraft communications at the European Space Operations Centre (ESOC), in Darmstadt, Germany via the agency’s 35 meter deep-space tracking station in New Norcia, Australia.

“All looks good,” says Rosetta Spacecraft Operations Manager Sylvain Lodiot, according to an ESA operations tweet.

CATP is part of the final series of ten orbit correction maneuvers (OCM’s) that culminates with the final thruster firing slated for Aug. 6 dubbed the Close Approach Trajectory – Insertion (CATI) burn.

“The CATI burn will reduce the relative velocity to about 1 m/s,” says Lodiot. That’s about equivalent to human walking speed.

The CATI orbit insertion firing will slow Rosetta to essentially the same speed as a comet and place it in orbit at an initial stand-off distance of about 100 kilometers (62 miles).

Rosetta will initially be travelling in a series of 100 kilometer-long triangular arcs while firings thrusters at each apex. Further engine firings will gradually lower Rosetta’s altitude about Comet 67P until the spacecraft is captured by the comet’s gravity.

“All systems on the spacecraft are performing well and the entire team is looking forward to a smooth arrival,” says Lodiot.

It will study and map the wanderer composed of primordial ice, rock, dust and more and search for a suitable landing site for Philae.

The one-way signal time from Earth to Rosetta and Comet 67P is currently 22 minutes and 27 seconds as both loop around the Sun at a distance of some 555 million kilometres away from the Sun at this time. The short period comet is located between the orbits of Jupiter and Mars.

Rosetta will escort Comet 67P as they journey together inwards around the sun and then travel back out towards Jupiter’s orbit and investigate the physical properties and chemical composition of the comets nucleus and coma of ice and dust for some 17 months.

Rosetta was launched on 2 March 2004 on an Ariane 5 G+ rocket from Europe’s spaceport in Kourou, French Guiana.

You can watch Rosetta’s Aug. 6 orbital arrival live from 10:45-11:45 CEST via a livestream transmission from ESA’s spacecraft operations centre in Darmstadt, Germany.

Ken Kremer

August 1, 2014December 23, 2015 by Ken Kremer

Rosetta Closing in on Comet 67P/Churyumov-Gerasimenko after Decade Long Chase

ESA’s Rosetta Spacecraft nears final approach to Comet 67P/Churyumov-Gerasimenko in late July 2014. This collage of imagery from Rosetta combines Navcam camera images at right taken nearing final approach from July 25 to July 31, 2014, with OSIRIS wide angle camera image at left of comet’s coma on July 25 from a distance of around 3000 km. On July 31 Rosetta had approached to within 1327 km. Images to scale and contrast enhanced to show further detail. Credit: ESA/Rosetta/NAVCAM/OSIRIS/MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
Collage/Processing: Marco Di Lorenzo/Ken Kremer – kenkremer.com
Story updated[/caption]

The European Space Agency’s (ESA) Rosetta spacecraft is at last rapidly closing in on its target destination, Comet 67P/Churyumov-Gerasimenko, after a decade long chase of 6.4 billion kilometers through interplanetary space. See imagery above and below.

As of today, Friday, August 1, ESA reports that Rosetta has approached the ‘rubber ducky looking’ comet to within a distance of less than 1153 kilometers. That distance narrows with each passing moment as the speeding robotic probe moves closer and closer to the comet while looping around the sun at about 55,000 kilometers per hour (kph).

Rosetta is now just 5 days away from becoming Earth’s first probe ever to rendezvous and enter orbit around a comet.

See above our image collage of Rosetta nearing final approach with the spacecrafts most recent daily Navcam camera images, all taken within the past week starting on July 25 and including up to the most recently release image snapped on July 31. The navcam images are all to scale to give the sense of the spacecraft approaching the comet and revealing ever greater detail as it grows in apparent size in the cameras field of view. The navcam images were also taken at about the same time of day each day.

The highest resolution navcam image yet of the two lobed comet – merged at a bright band – was taken on July 31 from a distance of 1327 kilometers and published within the past few hours by ESA today, Aug 1. It shows the best view yet of the surface features of the mysterious bright necked wanderer composed of primordial ice, rock, dust and more.

The Navcam collage is combined with an OSIRIS (Optical, Spectroscopic, and Infrared Remote Imaging System) wide angle camera view of the comet and its asymmetric coma of ice and dust snapped on July 25 from a distance of around 3000 km, and with an exposure time of 300 seconds. The OSIRIS image covers an area of about 150 x 150 km (90 mi x 90 mi). The images have been contrast enhanced to bring out more detail.

Scientists speculate that the comets bright neck region could be caused by differences in material or grain size or topological effects.

Rosetta’s history making orbital feat is slated for Aug. 6 following the final short duration orbit insertion burns on Aug. 3 and Aug. 6 to place Rosetta into orbit at an altitude of about 100 kilometers (62 miles) where it will study and map the 4 kilometer wide comet for some 17 months.

The comet rotates around once every 12.4 hours.

Crop from the 31 July processed image of comet 67P/Churyumov-Gerasimenko, to focus on the comet nucleus. Credits: ESA/Rosetta/NAVCAM

“If any glitches in space or on ground had delayed the most recent burns, orbital mechanics dictate that we’d only have had a matter of a few days to fix the problem, re-plan the burn and carry it out, otherwise we run the risk of missing the comet,” says Trevor Morley, a flight dynamics specialist at ESOC.

In November 2014 the Rosetta mothership will deploy the Philae science lander for the first ever attempt to land on a comet’s nucleus using harpoons to anchor itself to the surface while the comet is rotating.

As Rosetta edges closer on its final lap, engineers at mission control at the European Space Operations Centre (ESOC), in Darmstadt, Germany have commanded the probes navigation camera (navcam) to capture daily images while the other science instruments also collect measurements analyzing the comets physical characteristics and chemical composition in detail.

ESA’s Rosetta Spacecraft nears final approach to Comet 67P/Churyumov-Gerasimenko in late July 2014. This image collage from Rosetta combines Navcam camera images taken nearing final approach from July 25 (3000 km distant) to July 31, 2014 (1327 km distant). Top row shows images as seen by spacecraft. Bottom row shows images rotated to same orientation. Images to scale and contrast enhanced to show further detail. Credit: ESA/Rosetta/NAVCAM. Collage/Processing: Marco Di Lorenzo/Ken Kremer

The probe has already discovered that the comet’s surface temperature is surprisingly warm at –70ºC, which is some 20–30ºC warmer than predicted. This indicates the surface is too hot to be covered in ice and must instead have a dark, dusty crust, says ESA.

Comet 67P/Churyumov-Gerasimenko is a short period comet some 555 million kilometres from the Sun at this time, about three times further away than Earth and located between the orbits of Jupiter and Mars.

You can watch the Aug. 6 orbital arrival live via a livestream transmission from ESA’s spacecraft operations centre in Darmstadt, Germany.

While you were reading this the gap between the comet and Rosetta closed to less than 1000 kilometers!

The coma of Rosetta's target comet as seen with the OSIRIS wide-angle camera. The image spans 150 km and was taken on 25 July 2014 with an exposure time of 330 seconds. The greyscale relates to the particle density in the coma, with highest density close to the nucleus, becoming more diffuse further away. The hazy circular structure on the right is an artefact. The nucleus is also overexposured. The specks and the streaks in the background are attributed to background stars and cosmic rays. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA — The coma of Rosetta’s target comet as seen with the OSIRIS wide-angle camera. The image spans 150 km and was taken on 25 July 2014 with an exposure time of 330 seconds. The greyscale relates to the particle density in the coma, with highest density close to the nucleus, becoming more diffuse further away. The hazy circular structure on the right is an artefact. The nucleus is also overexposured. The specks and the streaks in the background are attributed to background stars and cosmic rays. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Stay tuned here for Ken’s continuing Curiosity, Opportunity, Orion, SpaceX, Boeing, Orbital Sciences, commercial space, MAVEN, MOM, Mars and more Earth and Planetary science and human spaceflight news.

Ken Kremer

Birthday cakes at @ESA_Rosetta Flight Dynamics are taking strange binary shapes these days... #ESOC. Credit: ESA — Birthday cakes at @ESA_Rosetta Flight Dynamics are taking strange binary shapes these days… #ESOC. Credit: ESA

July 31, 2014December 23, 2015 by Jason Major

New Image of Rosetta’s Comet Reveals So Much More

Comet 67P/Churyumov-Gerasimenko imaged by OSIRIS on July 29, 2014

WOW! We’re really getting to the good stuff now! This is no computer-generated shape model, this is the real deal: the double-lobed nucleus of Comet 67P/C-G, as imaged by Rosetta’s OSIRIS (Optical, Spectroscopic, and Infrared Remote Imaging System) narrow-angle camera on Tuesday, July 29. At the time just about a week away from making its arrival, ESA’s spacecraft was 1,950 km (1,211 miles) from the comet when this image was taken. (That’s about the distance between Providence, Rhode Island and Miami, Florida… that’s one fancy zoom lens, Rosetta!)

Comet 67P/Churyumov-Gerasimenko was imaged on 14 July 2014 by OSIRIS, Rosetta’s scientific imaging system, from a distance of approximately 12 000 km. This movie uses a sequence of 36 interpolated images each separated by 20 minutes, providing a 360° preview of the complex shape of the comet. (ESA) — Comet 67P/Churyumov-Gerasimenko imaged on July 14, 2014 by OSIRIS from a distance of approximately 12,000 km. (ESA)

This latest image reveals some actual surface features of the 4-km-wide comet, from a few troughs and mounds to the previously-noted bright band around the “neck” connecting the two lobes. The resolution in the July 29 OSIRIS image is 37 meters per pixel.

Since Rosetta is quickly closing the gap between itself and the comet we can only expect better images to come in the days ahead, so stay tuned — this is going to be an exciting August!

Keep up with the latest news on ESA’s Rosetta blog here, and find out where exactly Rosetta and Comet 67P/C-G are in the Solar System here.

Watch: Once Upon a Time There Was a Spacecraft Called Rosetta

Image credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Source: ESA

July 29, 2014December 23, 2015 by Ken Kremer

Scientists Discover 101 Geysers Erupting at Saturn’s Intriguing Icy Moon Enceladus

This dramatic view looks across the region of Enceladus' geyser basin and down on the ends of the Baghdad and Damascus fractures that face Saturn. The image, which looks approximately in the direction of Saturn, was taken from a more elevated viewpoint than other Cassini survey images of this area of the moon's south pole. Credit: NASA/JPL-Caltech/SSI

Scientists analyzing the reams of data from NASA’s Cassini orbiter at Saturn have discovered 101 geysers erupting from the intriguing icy moon Enceladus and that the spewing material of liquid water likely originates from an underground sea located beneath the tiny moons ice shell, according to newly published research.

The geysers are composed of tiny icy particles, water vapor and trace amounts of simple organic molecules. They were first sighted in Cassini imagery snapped during flyby’s of the 310-mile-wide (500 kilometers wide) moon back in 2005 and immediately thrust Enceladus forward as a potential abode for alien life beyond Earth and prime scientific inquisition.

Liquid water, organic molecules and an energy source are the key requirements for life as we know it.

The eruptions emanated from a previously unknown network of four prominent “tiger stripe” fractures, named Damascus, Baghdad, Cairo and Alexandria sulci, located at the south polar region of Saturn’s sixth largest moon.

Using imagery gathered over nearly seven years of surveys by Cassini’s cameras, researchers generated a survey map of the 101 geysers erupting from the four tiger strips.

This artist's rendering shows a cross-section of the ice shell immediately beneath one of Enceladus' geyser-active fractures, illustrating the physical and thermal structure and the processes ongoing below and at the surface. Image Credit: NASA/JPL-Caltech/Space Science Institute — This artist’s rendering shows a cross-section of the ice shell immediately beneath one of Enceladus’ geyser-active fractures, illustrating the physical and thermal structure and the processes ongoing below and at the surface. Image Credit: NASA/JPL-Caltech/Space Science Institute

The new findings and theories on the physical nature of how the geysers erupt have been published in two articles in the current online edition of the Astronomical Journal.

Scientists had initially postulated that the origin of the geysers could be frictional heating generated from back and forth rubbing of the opposing walls of the tiger stripe fractures that converted water ice into liquids and vapors. Another theory held that the opening and closing of the fractures allowed water vapor from below to reach the surface.

The geysers locations was eventually determined to coincide with small local hot spots erupting from one of the tiger stripe fractures after researchers compared low resolution thermal emission maps with the geysers’ locations and found the greatest activity at the warmest spots.

After later high-resolution data was collected in 2010 by Cassini’s heat-sensing instruments the geysers were found to coincide with small-scale hot spots, measuring only a few dozen feet (or tens of meters) across.

“Once we had these results in hand we knew right away heat was not causing the geysers, but vice versa,” said Carolyn Porco, leader of the Cassini imaging team from the Space Science Institute in Boulder, Colorado, and lead author of the first paper. “It also told us the geysers are not a near-surface phenomenon, but have much deeper roots.”

This graphic shows a 3-D model of 98 geysers whose source locations and tilts were found in a Cassini imaging survey of Enceladus' south polar terrain by the method of triangulation. While some jets are strongly tilted, it is clear the jets on average lie in four distinct "planes" that are normal to the surface at their source location. Image credit: NASA/JPL-Caltech/Space Science Institute — This graphic shows a 3-D model of 98 geysers whose source locations and tilts were found in a Cassini imaging survey of Enceladus’ south polar terrain by the method of triangulation. While some jets are strongly tilted, it is clear the jets on average lie in four distinct “planes” that are normal to the surface at their source location. Image credit: NASA/JPL-Caltech/Space Science Institute

“Thanks to recent analysis of Cassini gravity data, the researchers concluded the only plausible source of the material forming the geysers is the sea now known to exist beneath the ice shell. They also found that narrow pathways through the ice shell can remain open from the sea all the way to the surface, if filled with liquid water,” according to a NASA press release.

These are very exciting results in the search for life beyond Earth and clearly warrant a follow up mission.

“In casting your sights on the geysering glory of Enceladus, you are looking at frozen mist that originates deep within the solar system’s most accessible habitable zone,” writes Porco in her Captain’s Log summary of the new findings.

Surveyor's Map of Enceladus' Geyser Basin - On this polar stereographic map of Enceladus' south polar terrain, all 100 geysers have been plotted whose source locations have been determined in Cassini's imaging survey of the moon's geyser basin. Credit: NASA/JPL-Caltech/SSI — Surveyor’s Map of Enceladus’ Geyser Basin – On this polar stereographic map of Enceladus’ south polar terrain, all 101 geysers have been plotted whose source locations have been determined in Cassini’s imaging survey of the moon’s geyser basin. Credit: NASA/JPL-Caltech/SSI

The Cassini-Huygens mission is a cooperative project between NASA, the European Space Agency (ESA) and the Italian Space Agency (ASI). Cassini was launched by a Titan IV rocket in 1997 and arrived at Saturn in 2004.

In 2005 Cassini deployed the Huygens probe which landed on Titan, Saturn’s largest moon sporting oceans of organic molecules and another prime location in the search for life.

The Cassini mission will conclude in 2017 with an intentional suicide dive into Saturn to prevent contamination on Titan and Enceladus – but lots more breathtaking science will be accomplished in the meantime!

Stay tuned here for Ken’s Earth & Planetary science and human spaceflight news.

Ken Kremer

July 26, 2014December 23, 2015 by Ken Kremer

James Webb Space Telescope’s Giant Sunshield Test Unit Unfurled First Time

The sunshield test unit on NASA's James Webb Space Telescope is unfurled for the first time. Credit: NASA

GODDARD SPACE FLIGHT CENTER, MD – The huge Sunshield test unit for NASA’s James Webb Space Telescope (JWST) has been successfully unfurled for the first time in a key milestone ahead of the launch scheduled for October 2018.

Engineers stacked and expanded the tennis-court sized Sunshield test unit last week inside the cleanroom at a Northrop Grumman facility in Redondo Beach, California.

NASA reports that the operation proceeded perfectly the first time during the test of the full-sized unit.

The Sunshield and every other JWST component must unfold perfectly and to precise tolerances in space because it has not been designed for servicing or repairs by astronaut crews voyaging beyond low-Earth orbit into deep space, William Ochs, Associate Director for JWST at NASA Goddard told me in an exclusive interview.

Artist’s concept of the James Webb Space Telescope (JWST) with Sunshield at bottom. Credit: NASA/ESA

The five layered Sunshield is the largest component of the observatory and acts like a parasol.

Its purpose is to protect Webb from the suns heat and passively cool the telescope and its quartet of sensitive science instruments via permanent shade to approximately 45 kelvins, -380 degrees F, -233 C.

The kite-shaped Sunshield provides an effective sun protection factor or SPF of 1,000,000. By comparison suntan lotion for humans has an SPF of 8 to 40.

Two sides of the James Webb Space Telescope (JWST). Credit: NASA

The extreme cold is required for the telescope to function in the infrared (IR) wavelengths and enable it to look back in time further than ever before to detect distant objects.

The shield separates the observatory into a warm sun-facing side and a cold anti-sun side.

Its five thin membrane layers also provides a stable thermal environment to keep the telescopes 18 primary mirror segments properly aligned for Webb’s science investigations.

JWST is the successor to the 24 year old Hubble Space Telescope and will become the most powerful telescope ever sent to space.

The Webb Telescope is a joint international collaborative project between NASA, the European Space Agency (ESA) and the Canadian Space Agency (CSA).

NASA has overall responsibility and Northrop Grumman is the prime contractor for JWST.

Webb will launch folded up inside the payload fairing of an ESA Ariane V ECA rocket from the Guiana Space Center in Kourou, French Guiana.

In launch configuration, the Sunshield will surround the main mirrors and instruments like an umbrella.

During the post launch journey to the L2 observing orbit at the second Sun-Earth Lagrange point nearly a million miles (1.5 million Km) from Earth, the telescopes mirrors and sunshield will begin a rather complex six month long unfolding and calibration process.

The science instruments have been mounted inside the ISIM science module and are currently undergoing critical vacuum chamber testing at NASA Goddard Space Flight Center which provides overall management and systems engineering.

Gold coated flight spare of a JWST primary mirror segment made of beryllium and used for test operations inside the NASA Goddard clean room. Credit: Ken Kremer- kenkremer.com

The mirror segments have arrived at NASA Goddard where I’ve had the opportunity to observe and report on work in progress.

Stay tuned here for Ken’s continuing JWST, MMS, ISS, Curiosity, Opportunity, SpaceX, Orbital Sciences, Boeing, Orion, MAVEN, MOM, Mars and more Earth and Planetary science and human spaceflight news.

Ken Kremer

Sunshield test unit on NASA's James Webb Space Telescope is unfurled for the first time at Northrup Grumman. Credit: NASA — Sunshield test unit on NASA’s James Webb Space Telescope is unfurled for the first time at Northrup Grumman. Credit: NASA

July 21, 2014December 23, 2015 by Jason Major

Once Upon a Time There Was a Spacecraft Called Rosetta…

The road to a comet isn't an easy one! Luckily Rosetta and Philae have a lot of help.

…and that time is now! ESA’s Rosetta spacecraft is just over a mere two weeks away from its arrival at Comet 67P/Churyumov-Gerasimenko (which has recently surprised everyone with its binary “rubber duckie” shape) and the excitement continues to grow — and rightfully so, since after ten years traveling through the Solar System Rosetta is finally going to achieve its goal of being the first spacecraft to orbit a comet!

As part of the “Are We There Yet” campaign to encourage public participation in this historic space exploration event, ESA has released the next installment of Rosetta’s story in adorable animated format. Check it out above, and feel free to fall in love with a solar-powered spacecraft.

Keep up with Rosetta’s journey on the ESA website here, and enter the #RosettaAreWeThereYet contest by sharing your photos here (you could win a trip to ESA’s Operations Center in Darmstadt, Germany in November for Philae’s landing party!)

Video: ESA